White rot fungi are wood-decaying fungi which grow on a ligno-cellulose base as opposed to coprophilous fungi, for example, the Champignon mushroom, which grow by decomposing dung or compost. Examples of edible wood-rotting fungi include the abalone or oyster mushrooms such as Pleurotus cystidiosus (P. abalonus), P. ostreatus (both grey and white types), P. cornucopia, P. sajor caju and also the Shiitake or Chinese black forest mushroom known by the botanical name of Lentinus edodes. Of these, the Shiitake mushroom is the most difficult to grow because it grows only on wood whereas the other mushrooms will grow on almost any sort of cellulose base such as cotton waste or straw. The Shiitake mushroom apparently requires lignin as well as cellulose as a base for growth.
The traditional manner of cultivating Shiitake mushrooms is by the inoculation of wooden blocks with spawn. The blocks are left for many months to enable the spawn to grow through the block, after which fruiting occurs. Cultivation is chancy, and yield and time to fruiting are not particularly satisfactory.
The blocks of wood used for this type of cultivation are temperate hardwoods, such as beech and oak, of the Fagaceae family which are readily available in countries in Northern Europe and in Japan.